gnu: bash-completion: Search for completion modules in profiles.

* gnu/packages/patches/bash-completion-directories.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/bash.scm (bash-completion)[source]: Use it.

gnu-system.am

@@ -364,6 +364,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/automake-skip-amhello-tests.patch	\
   gnu/packages/patches/avahi-localstatedir.patch		\
   gnu/packages/patches/avrdude-fix-libusb.patch			\
+  gnu/packages/patches/bash-completion-directories.patch	\
   gnu/packages/patches/bowtie-fix-makefile.patch		\
   gnu/packages/patches/bigloo-gc-shebangs.patch			\
   gnu/packages/patches/binutils-ld-new-dtags.patch		\

gnu/packages/bash.scm

@@ -19,6 +19,7 @@
 
 (define-module (gnu packages bash)
   #:use-module (guix licenses)
+  #:use-module (gnu packages)
   #:use-module (gnu packages ncurses)
   #:use-module (gnu packages readline)
   #:use-module (gnu packages bison)
@@ -218,7 +219,9 @@ without modification.")
                     "bash-completion-" version ".tar.bz2"))
               (sha256
                (base32
-                "0kxf8s5bw7y50x0ksb77d3kv0dwadixhybl818w27y6mlw26hq1b"))))
+                "0kxf8s5bw7y50x0ksb77d3kv0dwadixhybl818w27y6mlw26hq1b"))
+              (patches
+               (list (search-patch "bash-completion-directories.patch")))))
     (build-system gnu-build-system)
     (synopsis "Bash completions for common commands")
     (description

gnu/packages/patches/bash-completion-directories.patch

@@ -0,0 +1,33 @@
+Bash-completion is written with FHS in mind where completion scripts
+all get added to /usr/share/bash-completion/completions and are picked
+up by the dynamic completion loader from there---whether they are
+part of bash-completion or installed by another package.
+
+On Guix systems, we want not only to search within bash-completion's own
+directory, but also in the user's profile and in the system profile.
+This is what this patch does.
+
+--- bash-completion-2.1/bash_completion	2015-03-11 09:45:45.056846446 +0100
++++ bash-completion-2.1/bash_completion	2015-03-11 09:52:43.248159504 +0100
+@@ -1928,9 +1928,20 @@ _completion_loader()
+     local compfile=./completions
+     [[ $BASH_SOURCE == */* ]] && compfile="${BASH_SOURCE%/*}/completions"
+     compfile+="/${1##*/}"
++    local base="${1##*/}"
+ 
++    # Look for completion files in the user and global profiles and
++    # lastly in 'bash-completion' itself.
++    for file in                                                                 \
++        "$HOME/.guix-profile/share/bash-completion/completions/$base"           \
++        "$HOME/.guix-profile/etc/bash_completion.d/$base"                       \
++        "/run/current-system/profile/share/bash-completion/completions/$base"   \
++        "/run/current-system/profile/etc/bash_completion.d/$base"               \
++        "$compfile"
++    do
+     # Avoid trying to source dirs; https://bugzilla.redhat.com/903540
+-    [[ -f "$compfile" ]] && . "$compfile" &>/dev/null && return 124
++        [[ -f "$file" ]] && . "$file" &>/dev/null && return 124
++    done
+ 
+     # Need to define *something*, otherwise there will be no completion at all.
+     complete -F _minimal "$1" && return 124